Novak Djokovic, the world No2 from Serbia, has beaten Rafael Nadal twice and Roger Federer three times this year. Photograph: Ella Ling/PA

Novak Djokovic, for the time being and maybe a little while to come, is unbeatable. Ask Rafael Nadal. Ask Roger Federer. Ask Tomas Berdych. The testimonies will be qualified, varying in enthusiasm, but unanimous: the Serb is the man to beat.

And if a reference from his closest and most demoralised contemporary is needed, ask Andy Murray. Nothing puts Murray's own wretched season in perspective so starkly as the success of his friend and rival, who was born a week after him, has gone nip and tuck with the Scot through the junior and senior ranks but, over the past three months, has moved further ahead than the gap of two places in the world rankings would suggest.

When Djokovic – ranked second by the computer but not by many of his peers – came from 5-2 down in the first set to beat Nadal in the final of the Miami Masters 1000 on Sunday, he continued a winning streak that began in the Australian Open 11 weeks ago. He also brought his victories over top-10 players in that time to eight.

These are not cheap victories. He has beaten Nadal twice, Federer three times, Berdych twice and Murray once. Such sustained excellence is rare; Nadal went on a 22-0 run on clay last year and, in 1984, John McEnroe strung together 39 wins before losing to Ivan Lendl in the French Open final. To emulate McEnroe's golden year – he was 82-3 over the season – Djokovic will have to win at least another slam, maybe not at Roland Garros, but Nadal's Wimbledon title is in his sights and the US Open as well.

If he stays free of injury and his form holds, Djokovic should overtake Nadal this summer at the top of the rankings because the Spaniard, 3,170 points ahead of him, has so many more to defend.

So irresistible has Djokovic been that even a switch to clay in Monte Carlo next week might not stop his rise. Nadal reckons Djokovic is a more serious threat to the No1 ranking he has held in his current reign since June last year than Federer – and some way ahead of world No4 Murray who has not won a set, let alone a match, since Djokovic blasted him in three sets to win the Australian Open.

"I think he's going to be No1," Nadal said, after Djokovic emerged a 4-6, 6-3, 7-6 winner of a final that dipped and soared for 3hr 22min. He reckoned Djokovic could reach the summit within two months. "It depends on my results on clay. For sure he will be there. If I am solid, if I [have] a very good clay-court season, we will see."

Djokovic is cautious. "I know I've had the best start of the season, no question about it," he said. "It's the best four months in my life. But it's only the start of the season. It's a bit early to talk about getting that top spot. Rafa is definitely the best player in the world now.

"I need to play consistently well throughout the whole year. We all know that clay court is his favourite surface – and I've never beaten Rafa on clay."

Few have. He remains the king of the red dirt and, on form, the only player capable of keeping Djokovic in check.

As he said when he discovered tweeting recently, Djokovic feels he "can fly". For 24 consecutive matches (26 in all going back before Christmas to the Davis Cup), he has stepped on to courts in Melbourne, Dubai, California and Florida so sure of his tennis that those formidable opponents have taken only four sets off him.

When the best players do come at him, he raises his game, the memorable feature of his latest win over Nadal.

But he has attained more than dominance. He has matured. "You can't always expect to win," he said. "I accept every day of my life on the court as something new to learn, trying to take the best out of it and move on as a better player, better person. I'm still only 23."